CA1129970A - Microwave heating apparatus with resistive heaters - Google Patents
Microwave heating apparatus with resistive heatersInfo
- Publication number
- CA1129970A CA1129970A CA347,796A CA347796A CA1129970A CA 1129970 A CA1129970 A CA 1129970A CA 347796 A CA347796 A CA 347796A CA 1129970 A CA1129970 A CA 1129970A
- Authority
- CA
- Canada
- Prior art keywords
- heating
- switch
- chamber
- heater
- microwave
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000010438 heat treatment Methods 0.000 title claims abstract description 77
- 230000008878 coupling Effects 0.000 claims abstract description 30
- 238000010168 coupling process Methods 0.000 claims abstract description 30
- 238000005859 coupling reaction Methods 0.000 claims abstract description 30
- 230000002401 inhibitory effect Effects 0.000 claims description 2
- 230000015556 catabolic process Effects 0.000 abstract description 4
- 238000009413 insulation Methods 0.000 abstract description 4
- 229920000136 polysorbate Polymers 0.000 abstract 1
- 238000010276 construction Methods 0.000 description 2
- 230000000994 depressogenic effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000012212 insulator Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 208000003251 Pruritus Diseases 0.000 description 1
- 208000036366 Sensation of pressure Diseases 0.000 description 1
- 235000018936 Vitellaria paradoxa Nutrition 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000010411 cooking Methods 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 230000002829 reductive effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/64—Heating using microwaves
- H05B6/6414—Aspects relating to the door of the microwave heating apparatus
- H05B6/6417—Door interlocks of the microwave heating apparatus and related circuits
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/64—Heating using microwaves
- H05B6/647—Aspects related to microwave heating combined with other heating techniques
- H05B6/6482—Aspects related to microwave heating combined with other heating techniques combined with radiant heating, e.g. infrared heating
Abstract
ABSTRACT OF THE DISCLOSURE
A microwave heating apparatus comprises a heating chamber, a microwave generator and heating resistors selectively connected through first and second switches to a power supply, and a control circuit connected through the first switch to the power supply. The heating apparatus also comprises heating resistor coupling units each including a displaceable member and a third switch. The displace-able member is displaced when the heater end is inserted to a predetermined position in the coupling unit, and the third switch is closed when the displaceable member is displaced. The third switch is connected in series be-tween the first switch and the control circuit. The high frequency radio wave generator or the heater is thus not connected to the power supply unless the heater end is com-pletely connected to the heater coupling unit. According-ly, it can prevent external leakage of microwaves, insu-lation breakdown or other related incidents.
A microwave heating apparatus comprises a heating chamber, a microwave generator and heating resistors selectively connected through first and second switches to a power supply, and a control circuit connected through the first switch to the power supply. The heating apparatus also comprises heating resistor coupling units each including a displaceable member and a third switch. The displace-able member is displaced when the heater end is inserted to a predetermined position in the coupling unit, and the third switch is closed when the displaceable member is displaced. The third switch is connected in series be-tween the first switch and the control circuit. The high frequency radio wave generator or the heater is thus not connected to the power supply unless the heater end is com-pletely connected to the heater coupling unit. According-ly, it can prevent external leakage of microwaves, insu-lation breakdown or other related incidents.
Description
/
37~:3 This invention relates to microwave heating apparatus which incorporates a heater provided in a foodheating chamber thereof for externally heating food disposed in the heating chamber.
Microwave heating apparatus isknown which provides heaters in a food heating chamber for externally heating the food. According to this conventional heating appa-ratus, microwaves from a microwave generator comprising for example a magnetron are suppiied to the heating cham-ber for cooking the food by heating it internally for ashort time in a microwave heating mode, and the food is externally heated to roast its surface by controlling the heating temperature of resistance heaters. In micro-wave heating apparat;u~-ofthis type,~the heaters provided in the heating chambe~ are commonly~subject to frequent detachment and~attachment as required when cleaning the interior~of the heating chamber or by the size of food to be cooked in the microwave~heating;mode. It is essen-ti~l to prevent any accident due to insulation breakdown, as well as improper contact, external leakage of micro-waves or other~incidents which may occur when the heaters have been~detache'~ and are again connected to a power ~ supply. Known heating apparatus has not, however, satis-;~ factorily eliminated the aforementioned problems.
According to the invention, there is provided a microwave heating apparatus comprising a heating chamber for , "!
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receiving food to be heated by said heating apparatus, said heating chamber having a wall with a bore there-through; a microwave generator for generating microwave energy to be conducted within said heating chamber for heating food within said chamber; a detachable resistive heating element for generating heat within said chamber for heating food within said chamber, said element having a terminal and an insulating sheath wrapped about a por-tion thereof, the sheath having a projection thereon; a control circuit for selectivel~ coupling power from a power source to said microwave generator and/or said re-sistive heating element; and a heater coupling means positioned substantially at the bore in said wall but on --the opposite side thereof from said heating chamber for ~:
(a) holding said detachable resistive heating element within said chamber and (b) coupling electrical power from said control circuit to said terminal of said resis-tive heating element, said heater coupling means including a displaceable member adapted to be displaced when an el-bow portion thereof fully contacts wi*h said projectionof said insulating sheath whenever said detachable resis-tive heating element is inserted through said bore to a predetermined position within said heater coupling means;
and a switch element, actuable by said displaceable mem-~ 25 ber, for inhibiting said control circuit from applying : power to said microwave generator and resistive heating :: element when said heating element is not inserted to said ` predetermined position.
The above and other fe:atures of the invention will be ~ ~ 30 apparent from the:following description of the disclosure -~ and the accompanying drawings, in which:
Figure 1 is a partial sectlonal view o a micro~ave ~: heating apparatus with reference to which the microwave heating apparatus according to this invention will be explained;
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Figure 2 is a partially enlarged sectional view of a known heater coupling unit as used in the apparatus shown in Figure l;
Figure 3 is a partially enlarged sectional view of one preEerred embodiment of the heater coupling unit used in the present invention but sho~ing the heater inserted to a predetermined position;
Figure 4 is a view similar to Figure 3, but showing the heater not yet inserted to the predetermined position;
Figure 5 is a circuit diagram of one example of the apparatus according to this invention; and Figure 6 i5 a partially enlarged sectional view of another preferred embodiment of the heater coupling unit.
With reference to Figures l and 2, the problems of the conventional heating apparatus will now be described in detail in order to facilitate understanding of the present invention.
In Figure l, the housing 11 of the microwave heating appa ratus includes an internal housing lla forming a heating chamber 14, and an external housing llb. The housing 11 also incorporates a space llc formed~between the housings lla and llb. The housing ll also has a door 15 provided at the front thereof to open or close the front face of the heating chamber 14. The housing ll internally houses a rack plate 16, an upper heater 17 above the rack plate plate 16 and a l~wer heater 18 below the rack plate 16 horizontally in the heating chamber 14. There are mounted a pair of heater coupling units l9a for holding the sup-ply términals of the heater 17 at the rear wall 19 of the internal housing lla, and a pair of heater coupling units l9b for holding the supply terminals of the heater 18 at , - ~ ~ . .
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the rear wall 19. The supply terminals of the respective heaters 17 and 18 are supplied from a power supply. A
tray 21 carrying food 20 is placed on the rack plate 16 in the housing 11. The housing 11 contains a microwave generator 22 including a magnetron in the space llc, which generator 22 supplies high frequency radio waves through a waveguide 23 into the heating chamber 14.
The prior art heater coupling unit as used for the heater coupling unit l9a, for example, in such a microwave hea-ting apparatus, is constructed as shown in Figure 2. InFigure 2, at the rear wall 19 of the internal housing lla is perforated a hole or an opening 24, to the periphery of which is fi~ed one end of a known microwave attenuating tube 25 extending horizontally into the space llc of the housing 11. A plurality of contact members 26a, 26b, : of resilient metal are fixedly secured to the other end of the radio wave attenuating tube 25, and are grounded :.~
through the attenuating tube 25. Thus, the high frequency radio wave transmitted from the heating chamber 14: to the heater 17 ~and~-:attenuated via :
the attenuating tube 25 is introduced to a grounding cir-: cuit. The supply terminal of the heater 17 is inserted : through the central portion of the attenuating tube 25, interposed between~the contact membe.rs 26a and 26b, and connected at its leading end thereof to a connector 27, ~: to which a~voltage is applied. The~end portion of the -heater 17 is coated over a predetermined length thereof . e~cluding the leading end by a sheath 28 formed of an -; : insulator. The end of the sheath 28 adjacent the connec-tor 27 is protected by an insulating tube 29. The sheath 28 makes contact with the contact members 26a and 26b.
: : The end of the connector 27 making contact with the lea-ding end of the:heater 17 is~protected by an insulator 30.
The heater coupling~unit l9a i5 also entirely covered by a metallic hollow cylinder 31 having known microwave at-tenuating properkies.
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However, the heater coupling unit shown in Figure 2 has the following disadvantages. When the heater 17 is re-peatedly detached from and again attached to the heater coupling unit, the contact pressure between the contact members 26a, 26b, .... and the sheath 28 can ~ecome reduced until a gap occurs between the contact members 26a, 26b, ... and the sheathl28 and accordingly sparking takes place in the gap. ~hen this sparking occurs, the sheath 2R may be perforated thereby causing an insulation breakdown which could cause a fire. In addition, the microwaves picked up~by the~heater 17 readily pass through the gap into the connector 27 thereby resulting in an ex-ternal leakage of the microwaves. Accordingly, it thus becomes difficult to maintain the safety of the entire microwave heating apparatus.
Since the configuration of the high frequency heating apparatus according to the present invention is the same as shown in Figure 1, and since like reference numerals in the drawings designate parts of the same construction and operation/ the construction and operation of these parts will not be described any further except when neces-sary.
In Figure 3, ~here is fixed, to the outer periphery of the hole or opening 24 perforated in the internal housing lla of the housing 11, one end of a radio wave attenu-ating hollow cylinder 25 t to the other end of which cylinder 25 axe fixed the respective one ends of a plura-lity of contact members 32a, 32b, ... each formed of resilient metal and having a bent portion and an ~xten-sion. A metallic hollow cylinder 33, connected at oneend to the rear wall 19 and having the same operational efect as the metallic hollow cylinder 31 shown in Figure 2, is perforated with a hole or opening 33a. The contact member 32a provided at the position facing the opening 33a of the cylinder 33 is different in shape from "
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the contact member 32b. The contact member 32a is dis-placed at its extension extended throuyh the opening 33a in the direction designated by arrow 34 when the bent portion of the contact member 32a is urged in the direc-S tion similarly designated by the arrow 34. In the vici-nit~ of the opening 33a of the cylinder 33 is fixed a switch mounting plate 35, to which plate 35 is fixed a microswitch 17a having an actuator 17b. This microswitch 17a is closed by the actuator 17b when the extension cf the contact member 32a is displaced in the direction of the arrow 34. The supply terminal of the heater 17 is provided with an insulating sheath 37 corresponding to the insulating sheath 28 shown in Figure 2, an insula-ting tube 29, and a projection 37a at a predetermined position such that the projection 37a contacts with the members 32a and 32b elastically. When the supply termi-nal of the heater 17 is inserted at the position of the heater coupling unit l9a, the extension of the contact member 32a is displaced in the direction of the arrow 34 to thereby close the switch 17a via the actuator 17b.
When the microswitch 17a is closed, the leading end of the heater 17 is completely connected to the connector 27. Since the contact member 32a is pushed up by the projection 37a of the shaath 37, the sheath 37 makes com-plete contact with the contact member 32a. Thus, micro-waves transmitted via the h~ater 17 are introduced through the sheath 37, the contact member 32a, the radio wave attenuating cylinder 25 and the rear wall 19 into the grounding circuit.
As shown in Figure 4, when the voltage supply terminal of the heater 17 is not fully inserted into the predeter-mined position of the heater coupling unit l9a, then since the projection 37a of the shea~h 37 does not make contact with the bent portion of the contact member 32a, the contact member 32a is not displaced as predetermined.
Accordingl~, the actuator 17b is not operated and the , : , , : . .. . .
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microswitch 17a is not closed.
Referring now to Figure 5 showing one example of a circuit diagram of microwave heating apparatus according to this invention, the connection and operation of the micro-switch 17a will now be described in detail. A powersupply 40 is connected through first switch 41, second switches 42a, 42b, and changeover switch 43 to a micro-wave generator 44 including a magnetron 22a or to upper and lower heaters 17 and 18. The power supply 40 is also connected through the switch 41, the switch 17a provided at the heater coupling unit l9a of the upper heater 17, and the switch 18a provided at the heater coupling unit l9b of the lower heater 18, to a control circuit 45 for controlling the ON-OFF operation of the second switches 42a and 42b. The changeover switch 43 operates selec-tively to supply power to the microwave generator 44 and the heaters 17 and 18. The control circuit 45 contains a start switch 46 connected in series with the switches 17a and 18a, a timer switch 47a, a relay 48, a switch 42c connected in parallel with the start switch 46 for self-holding the relay 48, and a timer 47 connected in paral-lel with the relay~ 48. When the timer 47 is set at a predetermined time, the timer switch 47a is automatically closed, and is opened upon lapse of the predetermined 2S time. The s~itches 42a, 42b and 42c each incorporate nor-mally open contacts and are closed when the relay 48 is energized.
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In Figure 5, when the microwave generator 44 is selec-tively connected to the power supply 40 and at least one ; 30 o~ the uPper and lower heaters 17 and 18 such as, for example, the upper heater 17, is incompletely inserted into the heater coupling unit l9a as shown in Figure 4, the microswitch L7a is opened. Accordingly, even if the ~ start switch 46 is depressed, the microwave generator 44 ,~ 35 not operated. External leakage of microwaves is thus ': ~ :
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completely prevented. In a case where the contact pres-sure of the contact member 32a is weakened so that a gap occurs between the projection 37a and the curved portion of the contact member 32a, then since the microswitch 17a is not closed, external leakage of microwaves is similarly prevented. It should be understood from the foregoing descxiption that since the high frequency heating appara-tus of this invention is thus constructed and operated, it can readily prevent insulation breakdown, occurrence of fire, external leakage of microwaves or other related incidents.
It is noted that although the embodiment in which the projection 37a is provided at the sheath 37 of the heater 17 has been described with reference to Figure 3, the heater coupling unit may also be constructed according to the configuration shown in Figure 6. In Figure 6, the contact member 32a is displaced onl~ when it is depressed by the sheath 28 of the heater 17 thereby to close the microswitch 17a, but the microswitch 17a is not closed at the position where the heater 17 itself faces the curved portion of the contact member 32a.
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37~:3 This invention relates to microwave heating apparatus which incorporates a heater provided in a foodheating chamber thereof for externally heating food disposed in the heating chamber.
Microwave heating apparatus isknown which provides heaters in a food heating chamber for externally heating the food. According to this conventional heating appa-ratus, microwaves from a microwave generator comprising for example a magnetron are suppiied to the heating cham-ber for cooking the food by heating it internally for ashort time in a microwave heating mode, and the food is externally heated to roast its surface by controlling the heating temperature of resistance heaters. In micro-wave heating apparat;u~-ofthis type,~the heaters provided in the heating chambe~ are commonly~subject to frequent detachment and~attachment as required when cleaning the interior~of the heating chamber or by the size of food to be cooked in the microwave~heating;mode. It is essen-ti~l to prevent any accident due to insulation breakdown, as well as improper contact, external leakage of micro-waves or other~incidents which may occur when the heaters have been~detache'~ and are again connected to a power ~ supply. Known heating apparatus has not, however, satis-;~ factorily eliminated the aforementioned problems.
According to the invention, there is provided a microwave heating apparatus comprising a heating chamber for , "!
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receiving food to be heated by said heating apparatus, said heating chamber having a wall with a bore there-through; a microwave generator for generating microwave energy to be conducted within said heating chamber for heating food within said chamber; a detachable resistive heating element for generating heat within said chamber for heating food within said chamber, said element having a terminal and an insulating sheath wrapped about a por-tion thereof, the sheath having a projection thereon; a control circuit for selectivel~ coupling power from a power source to said microwave generator and/or said re-sistive heating element; and a heater coupling means positioned substantially at the bore in said wall but on --the opposite side thereof from said heating chamber for ~:
(a) holding said detachable resistive heating element within said chamber and (b) coupling electrical power from said control circuit to said terminal of said resis-tive heating element, said heater coupling means including a displaceable member adapted to be displaced when an el-bow portion thereof fully contacts wi*h said projectionof said insulating sheath whenever said detachable resis-tive heating element is inserted through said bore to a predetermined position within said heater coupling means;
and a switch element, actuable by said displaceable mem-~ 25 ber, for inhibiting said control circuit from applying : power to said microwave generator and resistive heating :: element when said heating element is not inserted to said ` predetermined position.
The above and other fe:atures of the invention will be ~ ~ 30 apparent from the:following description of the disclosure -~ and the accompanying drawings, in which:
Figure 1 is a partial sectlonal view o a micro~ave ~: heating apparatus with reference to which the microwave heating apparatus according to this invention will be explained;
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Figure 2 is a partially enlarged sectional view of a known heater coupling unit as used in the apparatus shown in Figure l;
Figure 3 is a partially enlarged sectional view of one preEerred embodiment of the heater coupling unit used in the present invention but sho~ing the heater inserted to a predetermined position;
Figure 4 is a view similar to Figure 3, but showing the heater not yet inserted to the predetermined position;
Figure 5 is a circuit diagram of one example of the apparatus according to this invention; and Figure 6 i5 a partially enlarged sectional view of another preferred embodiment of the heater coupling unit.
With reference to Figures l and 2, the problems of the conventional heating apparatus will now be described in detail in order to facilitate understanding of the present invention.
In Figure l, the housing 11 of the microwave heating appa ratus includes an internal housing lla forming a heating chamber 14, and an external housing llb. The housing 11 also incorporates a space llc formed~between the housings lla and llb. The housing ll also has a door 15 provided at the front thereof to open or close the front face of the heating chamber 14. The housing ll internally houses a rack plate 16, an upper heater 17 above the rack plate plate 16 and a l~wer heater 18 below the rack plate 16 horizontally in the heating chamber 14. There are mounted a pair of heater coupling units l9a for holding the sup-ply términals of the heater 17 at the rear wall 19 of the internal housing lla, and a pair of heater coupling units l9b for holding the supply terminals of the heater 18 at , - ~ ~ . .
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the rear wall 19. The supply terminals of the respective heaters 17 and 18 are supplied from a power supply. A
tray 21 carrying food 20 is placed on the rack plate 16 in the housing 11. The housing 11 contains a microwave generator 22 including a magnetron in the space llc, which generator 22 supplies high frequency radio waves through a waveguide 23 into the heating chamber 14.
The prior art heater coupling unit as used for the heater coupling unit l9a, for example, in such a microwave hea-ting apparatus, is constructed as shown in Figure 2. InFigure 2, at the rear wall 19 of the internal housing lla is perforated a hole or an opening 24, to the periphery of which is fi~ed one end of a known microwave attenuating tube 25 extending horizontally into the space llc of the housing 11. A plurality of contact members 26a, 26b, : of resilient metal are fixedly secured to the other end of the radio wave attenuating tube 25, and are grounded :.~
through the attenuating tube 25. Thus, the high frequency radio wave transmitted from the heating chamber 14: to the heater 17 ~and~-:attenuated via :
the attenuating tube 25 is introduced to a grounding cir-: cuit. The supply terminal of the heater 17 is inserted : through the central portion of the attenuating tube 25, interposed between~the contact membe.rs 26a and 26b, and connected at its leading end thereof to a connector 27, ~: to which a~voltage is applied. The~end portion of the -heater 17 is coated over a predetermined length thereof . e~cluding the leading end by a sheath 28 formed of an -; : insulator. The end of the sheath 28 adjacent the connec-tor 27 is protected by an insulating tube 29. The sheath 28 makes contact with the contact members 26a and 26b.
: : The end of the connector 27 making contact with the lea-ding end of the:heater 17 is~protected by an insulator 30.
The heater coupling~unit l9a i5 also entirely covered by a metallic hollow cylinder 31 having known microwave at-tenuating properkies.
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However, the heater coupling unit shown in Figure 2 has the following disadvantages. When the heater 17 is re-peatedly detached from and again attached to the heater coupling unit, the contact pressure between the contact members 26a, 26b, .... and the sheath 28 can ~ecome reduced until a gap occurs between the contact members 26a, 26b, ... and the sheathl28 and accordingly sparking takes place in the gap. ~hen this sparking occurs, the sheath 2R may be perforated thereby causing an insulation breakdown which could cause a fire. In addition, the microwaves picked up~by the~heater 17 readily pass through the gap into the connector 27 thereby resulting in an ex-ternal leakage of the microwaves. Accordingly, it thus becomes difficult to maintain the safety of the entire microwave heating apparatus.
Since the configuration of the high frequency heating apparatus according to the present invention is the same as shown in Figure 1, and since like reference numerals in the drawings designate parts of the same construction and operation/ the construction and operation of these parts will not be described any further except when neces-sary.
In Figure 3, ~here is fixed, to the outer periphery of the hole or opening 24 perforated in the internal housing lla of the housing 11, one end of a radio wave attenu-ating hollow cylinder 25 t to the other end of which cylinder 25 axe fixed the respective one ends of a plura-lity of contact members 32a, 32b, ... each formed of resilient metal and having a bent portion and an ~xten-sion. A metallic hollow cylinder 33, connected at oneend to the rear wall 19 and having the same operational efect as the metallic hollow cylinder 31 shown in Figure 2, is perforated with a hole or opening 33a. The contact member 32a provided at the position facing the opening 33a of the cylinder 33 is different in shape from "
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the contact member 32b. The contact member 32a is dis-placed at its extension extended throuyh the opening 33a in the direction designated by arrow 34 when the bent portion of the contact member 32a is urged in the direc-S tion similarly designated by the arrow 34. In the vici-nit~ of the opening 33a of the cylinder 33 is fixed a switch mounting plate 35, to which plate 35 is fixed a microswitch 17a having an actuator 17b. This microswitch 17a is closed by the actuator 17b when the extension cf the contact member 32a is displaced in the direction of the arrow 34. The supply terminal of the heater 17 is provided with an insulating sheath 37 corresponding to the insulating sheath 28 shown in Figure 2, an insula-ting tube 29, and a projection 37a at a predetermined position such that the projection 37a contacts with the members 32a and 32b elastically. When the supply termi-nal of the heater 17 is inserted at the position of the heater coupling unit l9a, the extension of the contact member 32a is displaced in the direction of the arrow 34 to thereby close the switch 17a via the actuator 17b.
When the microswitch 17a is closed, the leading end of the heater 17 is completely connected to the connector 27. Since the contact member 32a is pushed up by the projection 37a of the shaath 37, the sheath 37 makes com-plete contact with the contact member 32a. Thus, micro-waves transmitted via the h~ater 17 are introduced through the sheath 37, the contact member 32a, the radio wave attenuating cylinder 25 and the rear wall 19 into the grounding circuit.
As shown in Figure 4, when the voltage supply terminal of the heater 17 is not fully inserted into the predeter-mined position of the heater coupling unit l9a, then since the projection 37a of the shea~h 37 does not make contact with the bent portion of the contact member 32a, the contact member 32a is not displaced as predetermined.
Accordingl~, the actuator 17b is not operated and the , : , , : . .. . .
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microswitch 17a is not closed.
Referring now to Figure 5 showing one example of a circuit diagram of microwave heating apparatus according to this invention, the connection and operation of the micro-switch 17a will now be described in detail. A powersupply 40 is connected through first switch 41, second switches 42a, 42b, and changeover switch 43 to a micro-wave generator 44 including a magnetron 22a or to upper and lower heaters 17 and 18. The power supply 40 is also connected through the switch 41, the switch 17a provided at the heater coupling unit l9a of the upper heater 17, and the switch 18a provided at the heater coupling unit l9b of the lower heater 18, to a control circuit 45 for controlling the ON-OFF operation of the second switches 42a and 42b. The changeover switch 43 operates selec-tively to supply power to the microwave generator 44 and the heaters 17 and 18. The control circuit 45 contains a start switch 46 connected in series with the switches 17a and 18a, a timer switch 47a, a relay 48, a switch 42c connected in parallel with the start switch 46 for self-holding the relay 48, and a timer 47 connected in paral-lel with the relay~ 48. When the timer 47 is set at a predetermined time, the timer switch 47a is automatically closed, and is opened upon lapse of the predetermined 2S time. The s~itches 42a, 42b and 42c each incorporate nor-mally open contacts and are closed when the relay 48 is energized.
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In Figure 5, when the microwave generator 44 is selec-tively connected to the power supply 40 and at least one ; 30 o~ the uPper and lower heaters 17 and 18 such as, for example, the upper heater 17, is incompletely inserted into the heater coupling unit l9a as shown in Figure 4, the microswitch L7a is opened. Accordingly, even if the ~ start switch 46 is depressed, the microwave generator 44 ,~ 35 not operated. External leakage of microwaves is thus ': ~ :
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completely prevented. In a case where the contact pres-sure of the contact member 32a is weakened so that a gap occurs between the projection 37a and the curved portion of the contact member 32a, then since the microswitch 17a is not closed, external leakage of microwaves is similarly prevented. It should be understood from the foregoing descxiption that since the high frequency heating appara-tus of this invention is thus constructed and operated, it can readily prevent insulation breakdown, occurrence of fire, external leakage of microwaves or other related incidents.
It is noted that although the embodiment in which the projection 37a is provided at the sheath 37 of the heater 17 has been described with reference to Figure 3, the heater coupling unit may also be constructed according to the configuration shown in Figure 6. In Figure 6, the contact member 32a is displaced onl~ when it is depressed by the sheath 28 of the heater 17 thereby to close the microswitch 17a, but the microswitch 17a is not closed at the position where the heater 17 itself faces the curved portion of the contact member 32a.
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Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A microwave heating apparatus comprising:
a heating chamber for receiving food to be heated by said heating apparatus, said heating chamber having a wall with a bore therethrough;
a microwave generator for generating microwave energy to be conducted within said heating chamber for heating food within said chamber;
a detachable resistive heating element for generating heat within said chamber for heating food within said chamber, said element having a terminal and an insulating sheath wrapped about a portion thereof, the sheath having a projection thereon;
a control circuit for selectively coupling power from a power source to said microwave generator and/or said re-sistive heating element; and a heater coupling means positioned substantially at the bore in said wall but on the opposite side thereof from said heating chamber for (a) holding said detachable resistive heating element within said chamber and (b) coupling electrical power from said control circuit to said terminal of said resistive heating element, said heater coupling means including a displaceable member adapted to be displaced when an elbow portion thereof fully contacts with said projection of said insulating sheath whenever said detachable resis-tive heating element is inserted through said bore to a predetermined position within said heater coupling means;
and a switch element, actuable by said displaceable member, for inhibiting said control circuit from applying power to said microwave generator and resistive heating element when said heating element is not inserted to said pre-determined position.
a heating chamber for receiving food to be heated by said heating apparatus, said heating chamber having a wall with a bore therethrough;
a microwave generator for generating microwave energy to be conducted within said heating chamber for heating food within said chamber;
a detachable resistive heating element for generating heat within said chamber for heating food within said chamber, said element having a terminal and an insulating sheath wrapped about a portion thereof, the sheath having a projection thereon;
a control circuit for selectively coupling power from a power source to said microwave generator and/or said re-sistive heating element; and a heater coupling means positioned substantially at the bore in said wall but on the opposite side thereof from said heating chamber for (a) holding said detachable resistive heating element within said chamber and (b) coupling electrical power from said control circuit to said terminal of said resistive heating element, said heater coupling means including a displaceable member adapted to be displaced when an elbow portion thereof fully contacts with said projection of said insulating sheath whenever said detachable resis-tive heating element is inserted through said bore to a predetermined position within said heater coupling means;
and a switch element, actuable by said displaceable member, for inhibiting said control circuit from applying power to said microwave generator and resistive heating element when said heating element is not inserted to said pre-determined position.
2. A microwave heating apparatus according to Claim 1, including first and second detachable resistive heating elements provided so that said first heating element is provided at an upper portion of said heating chamber and said second heating element is provided at a lower portion of said heating chamber.
3. A high frequency heating apparatus according to Claim 1, wherein said heater coupling means further com-prises a microwave attenuating cylinder fixedly secured to said heating chamber wall about the periphery of said bore and extending from the opposite side thereof from said heating chamber.
4. A high frequency heating apparatus according to Claim 3, wherein said projection is formed by a portion of the insulating sheath that is thicker than the insulating sheath at the other portions thereof.
5. A high frequency heating apparatus according to Claim 1, wherein said control circuit comprises a series circuit of said switch element and further comprises a start switch for self-holding a relay for controlling the ON-OFF operation of a second switch, and a timer connec-ted in parallel with said relay such that when said switch element and start switch are closed and said timer is set at a predetermined time, said relay closes said second switch, and opens said second switch upon lapse of said predetermined time.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35246/79 | 1979-03-19 | ||
| JP1979035246U JPS55135396U (en) | 1979-03-19 | 1979-03-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1129970A true CA1129970A (en) | 1982-08-17 |
Family
ID=12436469
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA347,796A Expired CA1129970A (en) | 1979-03-19 | 1980-03-17 | Microwave heating apparatus with resistive heaters |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4298780A (en) |
| JP (1) | JPS55135396U (en) |
| AU (1) | AU530325B2 (en) |
| CA (1) | CA1129970A (en) |
| DE (1) | DE3010231C3 (en) |
| FR (1) | FR2452063A1 (en) |
| GB (1) | GB2047060B (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3047112C2 (en) * | 1980-12-13 | 1982-12-02 | G. Bauknecht Gmbh, 7000 Stuttgart | Electric oven with a microwave heating device and further electrical heating devices |
| DE3126094C2 (en) * | 1981-07-02 | 1984-06-20 | G. Bauknecht Gmbh, 7000 Stuttgart | Electric oven with a microwave heating device and other electric heating devices, including a removable grill heater |
| US4752664A (en) * | 1985-07-05 | 1988-06-21 | Sharp Kabushiki Kaisha | Microwave oven with a removably attached heater |
| US5189274A (en) * | 1989-06-13 | 1993-02-23 | Matsushita Electric Industrial Co., Ltd. | Heating method for microwave oven having heat element |
| US7129451B2 (en) * | 2004-09-28 | 2006-10-31 | Lg Electronics Inc. | Microwave oven |
| US11234299B2 (en) * | 2014-04-07 | 2022-01-25 | Whirlpool Corporation | System for warming up and/or cooking food with microwave detection |
| DE102014109729B3 (en) * | 2014-07-11 | 2015-08-20 | Miele & Cie. Kg | Cooking appliance and fixing system |
| GB201605100D0 (en) | 2016-03-24 | 2016-05-11 | Nicoventures Holdings Ltd | Vapour provision system |
| GB201605102D0 (en) | 2016-03-24 | 2016-05-11 | Nicoventures Holdings Ltd | Mechanical connector for electronic vapour provision system |
| GB201605101D0 (en) | 2016-03-24 | 2016-05-11 | Nicoventures Holdings Ltd | Electronic vapour provision system |
| GB201605105D0 (en) | 2016-03-24 | 2016-05-11 | Nicoventures Holdings Ltd | Vapour provision apparatus |
| RU2741664C2 (en) | 2016-07-22 | 2021-01-28 | Никовенчерс Трейдинг Лимитед | Case for device for providing vapour |
| CN106813275B (en) * | 2017-03-21 | 2023-04-07 | 珠海格力电器股份有限公司 | Microwave interlocking control switch and microwave cooker |
| WO2019033089A1 (en) * | 2017-08-11 | 2019-02-14 | Brava Home, Inc. | Configurable cooking systems and methods |
| EP4018784A4 (en) * | 2020-01-17 | 2022-09-28 | Samsung Electronics Co., Ltd. | Cooking appliance |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3196243A (en) * | 1963-02-26 | 1965-07-20 | Raytheon Co | High frequency heating system |
| US3700846A (en) * | 1970-04-30 | 1972-10-24 | Tokyo Shibaura Electric Co | High frequency heating apparatus |
| IT1007320B (en) * | 1973-08-10 | 1976-10-30 | Jega Jenewein & Gapp Gmbh | COOKING GRID FOR THERMOELECTRIC COMBINED OVENS WITH RA DIATIONS |
| JPS5843875B2 (en) * | 1977-07-11 | 1983-09-29 | 松下電器産業株式会社 | Heater device for high frequency heating device |
-
1979
- 1979-03-19 JP JP1979035246U patent/JPS55135396U/ja active Pending
-
1980
- 1980-03-12 AU AU56361/80A patent/AU530325B2/en not_active Ceased
- 1980-03-12 US US06/129,644 patent/US4298780A/en not_active Expired - Lifetime
- 1980-03-14 GB GB8008819A patent/GB2047060B/en not_active Expired
- 1980-03-17 CA CA347,796A patent/CA1129970A/en not_active Expired
- 1980-03-17 DE DE3010231A patent/DE3010231C3/en not_active Expired
- 1980-03-19 FR FR8006137A patent/FR2452063A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| DE3010231B2 (en) | 1981-02-19 |
| GB2047060A (en) | 1980-11-19 |
| FR2452063B1 (en) | 1983-03-11 |
| DE3010231C3 (en) | 1981-12-17 |
| AU5636180A (en) | 1980-09-25 |
| DE3010231A1 (en) | 1980-09-25 |
| FR2452063A1 (en) | 1980-10-17 |
| AU530325B2 (en) | 1983-07-14 |
| US4298780A (en) | 1981-11-03 |
| GB2047060B (en) | 1983-02-16 |
| JPS55135396U (en) | 1980-09-26 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |